Energy absorber for automobile safety belts

ABSTRACT

An energy absorber for automobile safety belts which comprises a mounting rigidly or non-rigidly coupled to the chassis, a take-up member which is rotatable relative to the mounting and a torsion bar located between the mounting and the take-up member such that when an impact force is sensed, the torsion bar absorbs the energy of the impact force.

United States Patent [191 Fiala ENERGY ABSORBER FOR AUTOMOBILE SAFETYBELTS [75] Inventor: Ernst Fiala, Berlin, Germany [73] Assignee:Wolf-Dieter Klink, Lindach,

Germany [22] Filed: May 26, 1971 [21] Appl. No.: 146,887

[30] Foreign Application Priority Data May 29, 1970 Germany P 20 26277.5

[52] US. Cl...... 242/107.4, 242/107 SB, 242/107.3, 297/386 [51] Int. ClA62b 35/00 [58] Field of Search 242/54, 107 R, 107 SB, 242/1074, 107.5,107.6, 99; 297/385, 386,

[111 amass June 26, 1973 [56] References Cited UNITED STATES PATENTS3,561,690 2/1971 Muskat 297/386 X 3,632,060 l/1972 Balder 242/l07.4 X

Primary Examiner-Werner H. Schroeder Attorney-Curt M. Avery, Arthur E.Wilfond, Herbert L. Lerner and Daniel J. Tick [5 7] ABSTRACT An energyabsorber for automobile safety belts which comprises a mounting rigidlyor non-rigidly coupled to the chassis, a take-up member which isrotatable relative to the mounting and a torsion bar located between themounting and the take-up member such that when an impact force issensed, the torsion bar absorbs the energy of the impact force.

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ENERGY ABSORBER FOR AUTOMOBILE SAFETY BELTS My invention relates to theabsorption of energy for restraining systems in passenger vehicles,particularly energy absorbers'for safety belts used therein.

Movement restraining systems, such as belts or seats, for passengervehicles must absorb substantial amounts of energy during accidentalimpact, and the forces acting on the body of the passenger must notexceed certain values to prevent injury. Existing systems fail toprovide for. sufficient energy absorption to prevent such injury.

An object of my invention is to provide a small, lightweight energyabsorbent system of the kind mentioned above which can absorb largeamounts of energy.

Another object of my invention is to provide such an energy absorbentsystem which can be used with present safety belts without significantmodification thereof.

Still another object of my invention is to provide such an energyabsorbent system which can be conveniently installed in automotivevehicles.

Another object of my invention is to provide an energy absorbent systemwhich can be used with twoand three-point seat belts and harnesses.

Other objects, advantages and features of the present invention willbecome'more apparent from the following description.

In accordance with my invention, the above objects are accomplished byproviding an energy absorber which consists of a take-up member fortransmitting the impact force to a rotatable mounting and a torsion barwhich connects the take-up member to the mounting and can absorb largeamounts of energy when the take-up member rotates relative to themounting.

The invention will be further described with reference to embodimentsthereof, illustrated by way of example on the accompanying drawings inwhich:

FIG. 1 is a longitudinal cross-sectional view through a first embodimentof execution of my invention;

FIG. 2 is a cross-sectional view through lines lI-Il of FIG. 1;

FIG. 3 is a longitudinal cross-sectional view through another embodimentof my invention;

FIG. 4 is a cross-sectional view along lines IV-IV of FIG. 3;

FIG. 5 is a longitudinal cross-sectional view through a thirdembodiment-of my invention;

FIG. 6-is a cross-sectional view through lines VI-VI of FIG. 5;

FIG. 7 is a longitudinal cross-sectional view through an automatic beltmechanism; and

FIG. 8 is 'a cross-sectional view through lines VIII- -VIII of FIG.'7.

Referring to the drawings, and in particular to FIGS. 1 and 2, there isshown a support which consists of a U- shaped bracket having left-handleg 3a, a right-hand leg 3b and a connecting base part 30. The base 3cis rigidly connected with the vehicle or the restraining system, andmay, for example, be bolted to the floor of the vehicle as the tie pointof one end of the safety belt. A sleeve 1 is rotatably supported in thelegs 3a and 3b with a force-transmitting part 2 wound thereon, such as asafety belt. The force-transmitting part can also .be a steel band or arope. A torsion rod 5 is located inside the sleeve 1 and is connected atits left end 5a with the sleeve 1 rigidly secured against rotation bylocking means, such as teeth or a square or hexagonal locking member.

Rotation of the sleeve 1 therefore results in the torsion rod 5 beingrotated along at its left end 5a. At its right end 4a, the torsion rodis also positively connected by means of a suitable tooth arrangement orby a square or hexagonal locking means with a flange 4. The flange 4, inturn, is connected against rotation, with the leg 3b of the U-bracket 3.Arrow 7 indicates the unwinding direction of the safety belt 2, and fortransmission of the torque in the U-bracket 3, a stiffening member 13can be provided between the legs 3a and 3b. As the belt 2 unwinds, thetorsion bar effects its shock absorbing action.

FIGS. 3 and 4 show another embodiment of my invention. In thisembodiment, the safety belt 2 is wound on a sleeve 1, which surrounds atorsion rod 5. The torsion rod 5 is connected at its left end 5a withthe sleeve 1 securely against rotation, and is connected at its rightend 4a with the flange 4 securely against rotation. End support legs 11and 12 are provided, their shape being shown in FIG. 4. These legs 11and 12 are secured against rotation and connected with each other bymeans of the two bolts 12a and 12b. The flange 4 is non-rotatablyconnected with the right-hand leg 11. The safety belt 2 has two ends 8and 9, which unwind around the two bolts 12b and 120, respectively, andtwist around the torsion rod 5 with the safety belt 2 being firmlyconnected with the sleeve 1. In order to obtain the same forcelimitation as with the embodiment of FIGS. 1 and 2, the diameter of thetorsion rod is larger, because the two belt ends act upon the sleeve 1with both wound on the sleeve 1.

According to the embodiment of FIGS. 3 and 4, the mounting has the twoparallel legs which are flanges and are held in a non-rotatable mutualrelation by means of the two connecting bolts 12a and 12b, wherein thetwo ends of the force-transmitting member or safety belt 2 are wound onthe take-up member from opposite sides and are led around the connectingbolts in such a manner that in the event of a stretching of the safetybelt 2 and the resulting rotation of the take-up member 5, the mountingis braced at the forcetransmitting part by means of the connectingbolts. Such a device can be inserted into a safety belt withoutdifficulty and does not have to be connected firmly with the chassisframe.

In the embodiment of FIGS. 1 and 2, two belts also can be used, forinstance, the shoulder and hip belt of a three-point harness.

FIGS. 5 and 6 show yet another embodiment of my invention. A sleeve 16is supported rotatably between legs 3a and 3b of a Ubracket mounting 3.The sleeve 16 surrounds the torsion rod 15, which has, at its center, asquare 15c engaging a correspondingly shaped opening in a constrictionof the sleeve 16. By providing a square, the sleeve is connected withthe center part of the torsion rod 15, and is secured against rotation.The torsion rod 15 also has, at its ends, two additional squares 15a and15b which engage correspondingly shaped openings in side plates 17a and17b. The plates 17a and 17b are rigidly connected with the adjoininglegs 3a and 3b. In the installed condition, the safety belt (not shown)is wound onthe sleeve 16. The unwinding of the safety belt results inrotation of the sleeve 16, and the forces caused by the twisting of thetorsion rod 15 act against this rotation. Also in this embodiment,

the connecting base part 3c of the bracket 3 is rigidly fixed with thevehicle or the restraining device, for instance, by bolts. Instead ofthe square shapes shown, tooth arrangements or other forms can also bechosen which prevent rotation of the elements at the joints. Instead ofa single belt, several belts can also be wound on the sleeve 16. In theembodiment of FIGS. 5 and 6, the torsion bar is non-rotatably supportedat its center with respect to the sleeve and rotatably in the mountingat its two ends.

The device according to my invention allows for the belt 2 to beprebiased as it is wound. The device can be located at several points,for instance, between the shoulder and the attachment to the vehicle(FIG. 2). It is also possible to combine the device with a belt buckleand with devices which increase the tension in the belt at the start ofan accident.

An automatic belt mechanism is shown in FIGS. 7 and 8. The take-upmember 18 is supported on a square 19 of the torsion rod 20 and on theother side in a gear 21. The torsion rod 20, itself, is supportedrotatably in a U-shaped support 22. A spiral spring 23 is attached, atone end, in a slot of the take-up member 18 and at its other end in anopening 24 of the rear wall of the support 22. By means of the spring23, the belt 2 is continuously wound on the take-up member 18 with aforce of about 300 ponds (grams). Underneath the take-up member 18, alocking lever 25 is arranged which is fulcrumed in cutouts in thesupport 22 and rest with its free end which has the form of a ballsocket, on the ball 26. The locking lever 25 is kept in the restposition by a spring 27, the spring 27 being matched to the mass of theball 26 in such a manner that a predetermined horizontal acceleration(about 5 m/sec or a rotation of the earth acceleration vector by morethan 30 causes a relative motion of the ball 26 with respect to thesupport 22, and the locking lever is lifted so far that the teeth of thegear 21 are blocked by one or several cogs arranged at the locking lever25. In this operating condition of the automatic belt mechanism, thebelt can be pulled from the take-up member 18 only through deformationof the torsion rod 20, so that the force acting on the belt is convertedinto deformation energy.

A torsion rod as the energy converter can be applied, according to theembodiment of FIGS. 7 and 8, to the automatic belt mechanism, in which aclutch is arranged between the torsion rod and the mounting, which isnot effective under normal driving conditions, so that the safety beltis unwound from the sleeve 1 as required and can be rewound by a springtensioned in the process. Only in the event of danger, the clutch isactuated by the inertial member 26 due to the accompanying velocitychange, in such a manner that one end of the torsion rod 20 becomesconnected and rigidly secured against rotation relative to the mounting22, while the other end of the torsion rod is rigidly connected with thesleeve on which the safety belt is wound.

In all the above embodiments, the forces occurring in the event of anaccidental shock are controlled best and transmitted to the passenger inthe most gentle manner if the torsion bar is provided with elastic andplastic deformability with only relatively little elastic deformabilityas compared to its plastic deformability, the plastic deformabilityoccurring only under excessive strain.

It has been found preferable that the torsion bar be stressedexclusively for torsion in the event of rotation between the mountingsand the take-up members.

Due to the compact form of the torsion rod, the elastic deformation issmall, as desired. After the elastic limit is exceeded, the plastictorsional deformation takes place which, through the choice of a toughmaterial, can stand three to five revolutions before fracture occurs. Inthis process, the safety belt unwinds from the take-up member, while theforce in the plastic deformation phase increases only relatively littleafter it had risen steeply during the elastic phase. The energy istherefore absorbed in the desired manner as deformation energy of thetorsion rod.

For compactness, in the embodiments above, the sleeves surround thecorresponding torsion bars.

It will thus be seen that the objects set forth above, among those madeapparent from the preceding description, are efficiently attained and,since certain changes may be made in the above apparatus withoutdeparting from the scope of the invention, it is intended that allmatter contained in the above description and shown in the accompanyingdrawings shall be interpreted as illustrative and not in a limitingsense.

I claim:

1. Energy absorber for restraining systems in passenger vehiclescomprising a take-up member, a forcetransmitting member and a mountingrotatable relative to said take-up member, and an elongated torsion barrotated about its longitudinal axis between said mounting and saidtake-up member for absorbing large amounts of energy when the take-upmember rotates relative to the mounting.

2. Energy absorber according to claim 1, wherein said torsion rod iscapable of being plastically deformed.

3. Energy absorber according to claim 2, wherein said torsion bar iscapable of being plastically deformed with said elastic deformabilitybeing relatively slight as compared to its plastic deformability.

4. Energy absorber according to claim 3, wherein said torsion bar isstressed only for torsion for accommodating rotation between saidmounting and said take-up member.

5. Energy absorber according to claim 1, wherein said mounting comprisesa U-shaped bracket having two legs connected with each othernon-rotatably, each of said legs having an opening to rotatably supportthe take-up member, said take-up member forming a sleeve.

6. Energy absorber according to claim 1, wherein said mounting isrigidly connected with the vehicle.

7. Energy absorber according to claim 1, wherein said force-transmittingmember is an automobile seat belt.

8. Energy absorber for restraining systems in passenger vehiclescomprising a take-up member, a forcetransmitting member and a mountingrotatable relative to said take-up member, said mounting comprising aU-shaped bracket having two legs connected with each othernon-rotatably, each of said legs having an opening to rotatably supportthe take-up member, said takeup member forming a sleeve, and a torsionbar rotated between said mounting and said take-up member for absorbinglarge amounts of energy when the take-up member rotates relative to themounting; said torsion bar being connected at one of its endsnon-rotatably with said' sleeve and at its other end non-rotatably withone of said legs via an intermediate member.

9. Energy absorber according to claim 8, wherein said intermediatemember is a flange having an opening with which said one end of thetorsion bar is in positive engagement.

10. Energy absorber for restraining systems in passenger vehiclescomprising a take-up member, a forcetransmitting member and a mountingrotatable relative to said take-up member, said mounting comprising aU-shaped bracket having two legs connected with each othernon-rotatably, each of said legs having an opening to rotatably supportthe take-up member, and a torsion bar rotated between said mounting andsaid takeup member for absorbing large amounts of energy when thetake-up member rotates relative to the mounting, said take-up memberforming a sleeve which surrounds said torsion bar.

11. Energy absorber for restraining systems in passenger vehiclescomprising a take-up member, a forcetransmitting member and a mountingrotatable relative to said take-up member, and a torsion bar rotatedbetween said mounting and said take-up member for absorbing largeamounts of energy when the take-up member rotates relative to themounting, said take-up member forming a sleeve, said torsion bar beingsupported at its center non-rotatably relative to said sleeve, and atboth of its ends non-rotatably in said mounting.

12. Energy absorber for restraining systems in passenger vehiclescomprising a take-up member, a forcetransmitting member and a mountingrotatable relative to said take-up member, and a torsion bar rotatedbetween said mounting and said take-up member for absorbing largeamounts of energy when the take-up member rotates relative to themounting, said mounting having two parallel legs formed of flanges, twoconnecting bolts holding said legs in a non-rotatable mutual relation,said force-transmitting member having two ends wound on said take-upmember from opposite sides and being fed around the respectiveconnecting bolts so that when said force-transmitting member stretchessaid take-up member rotates, and the mounting is braced at theforce-transmitting member by means of said connecting bolts.

13. Energy absorber for restraining systems in passenger vehiclescomprising a take-up member, a forcetransmitting member and a mountingrotatable relative to said take-up member, a torsion bar rotated betweensaid mounting and said take-up member for absorbing large amounts ofenergy when the take-up member rotates relative to the mounting, and aclutch means responsive to a horizontal acceleration or a rotation ofthe earth acceleration vector being connected between said torsion barand take-up member for blocking the rotation of said take-up member.

14. Energy absorber according to claim 13, wherein said clutch meanscomprises a gear rigidly connected with one end of the torsion bar and alever having a free end, having the form of a ball socket, said leverresting on a spherical inertial member and having blocking cogs whichengage with said gear in the coupled condition.

1. Energy absorber for restraining systems in passenger vehiclescomprising a take-up member, a force-transmitting member and a mountingrotatable relative to said take-up member, and an elongated torsion barrotated about its longitudinal axis between said mounting and saidtake-up member for absorbing large amounts of energy when the take-upmember rotates relative to the mounting.
 2. Energy absorber according toclaim 1, wherein said torsion rod is capable of being plasticallydeformed.
 3. Energy absorber according to claim 2, wherein said torsionbar is capable of being plastically deformed with said elasticdeformability being relatively slight as compared to its plasticdeformability.
 4. Energy absorber according to claim 3, wherein saidtorsion bar is stressed only for torsion for accommodating rotationbetween said mounting and said take-up member.
 5. Energy absorberaccording to claim 1, wherein said mounting comprises a U-shaped brackethaving two legs connected with each other non-rotatably, each of saidlegs having an opening to rotatably support the take-up member, saidtake-up member forming a sleeve.
 6. Energy absorber according to claim1, wherein said mounting is rigidly connected with the vehicle. 7.Energy absorber according to claim 1, wherein said force-transmittingmember is an automobile seat belt.
 8. Energy absorber for restrainingsystems in passenger vehicles comprising a take-up member, aforce-transmitting member and a mounting rotatable relative to saidtake-up member, said mounting comprising a U-shaped bracket having twolegs connected with each other non-rotatably, each of said legs havingan opening to rotatably support the take-up member, said take-up memberforming a sleeve, and a torsion bar rotated between said mounting andsaid take-up member for absorbing large amounts of energy when thetake-up member rotates relative to the mounting; said torsion bar beingconnected at one of its ends non-rotatably with said sleeve and at itsother end non-rotatably with one of said legs via an intermediatemember.
 9. Energy absorber according to claim 8, wherein saidintermediate member is a flange having an opening with which said oneend of the torsion bar is in positive engagement.
 10. Energy absorberfor restraining systems in passenger vehicles comprising a take-upmember, a force-transmitting member and a mounting rotatable relative tosaid take-up member, said mounting comprising a U-shaped bracket havingtwo legs connected with each other non-rotatably, each of said legshaving an opening to rotatably support the take-up member, and a torsionbar rotated between said mounting and said take-up member for absorbinglarge amounts of energy when the take-up member rotates relative to themounting, said take-up member forming a sleeve which surrounds saidtorsion bar.
 11. Energy absorber for restraining systems in passengervehicles comprising a take-up member, a force-transmitting member and amounting rotatable relative to said take-up member, and a torsion barrotated between said mounting and said take-up member for absorbinglarge amounts of energy when the take-up member rotates relative to themounting, said take-up member forming a sleeve, said torsion bar beingsupported at its center non-rotatably relative to said sleeve, and atboth of its ends non-rotatably in said mounting.
 12. Energy absorber forrestraining systems in passenger vehicles comprising a take-up member, aforce-tRansmitting member and a mounting rotatable relative to saidtake-up member, and a torsion bar rotated between said mounting and saidtake-up member for absorbing large amounts of energy when the take-upmember rotates relative to the mounting, said mounting having twoparallel legs formed of flanges, two connecting bolts holding said legsin a non-rotatable mutual relation, said force-transmitting memberhaving two ends wound on said take-up member from opposite sides andbeing fed around the respective connecting bolts so that when saidforce-transmitting member stretches said take-up member rotates, and themounting is braced at the force-transmitting member by means of saidconnecting bolts.
 13. Energy absorber for restraining systems inpassenger vehicles comprising a take-up member, a force-transmittingmember and a mounting rotatable relative to said take-up member, atorsion bar rotated between said mounting and said take-up member forabsorbing large amounts of energy when the take-up member rotatesrelative to the mounting, and a clutch means responsive to a horizontalacceleration or a rotation of the earth acceleration vector beingconnected between said torsion bar and take-up member for blocking therotation of said take-up member.
 14. Energy absorber according to claim13, wherein said clutch means comprises a gear rigidly connected withone end of the torsion bar and a lever having a free end, having theform of a ball socket, said lever resting on a spherical inertial memberand having blocking cogs which engage with said gear in the coupledcondition.